Incandescent electric lamp



Feb. 28, 1933. J QUESSEQUE 1,899,587

INCANDESCENT ELECTRIC LQAMP Filed Sepi}. 24, 1931 [1W5 N TUE. VJL'ANGUESSEQUL',

Ms A? TURKEY Patented Feb. 28, 1933 UNITED STATES PATENT OFFICE JEANQUESSEQUE, OF ISSY-LES-MOULINEAUX, FRANCE, ASSIGNOR TO GENERAL ELEC:

TRIC COMPANY, A; CORPORATION OF NEW YORK momnnscnn'r' mac'rmo LAMPApplication filed September 24, 1981, Serial 110. {564,888, and inFrance October 31, 1930.

My invention relates to incandescent electric lamps and moreparticularly to such lamps provided with a gas filling.

The object of my invention is to provide a simple and effective means ofpreventing the blackening of the bulbs of such lamps.

After a lamp has been burning one thousand hours, blackening of thebulb, with a resulting loss of luminous efiiciency, becomes noticeable.Said blackening is due to the disintegration of the filament, wherebytungsten particles, torn from the hot filament, are carried by theconvection currents to the walls of the bulb, where they are deposited.Due

to the loss of luminous efliciency, it may be more economical to replacea lamp thus blackened with a new one before the filament is broken.Blackening of the bulb becomes an increasingly greater problem in thehigher power lamps.

The appearance of a lamp is also impaired.

by the blackening of the bulb, which is an especially importantobjection in lamps which are used for decorative purposes.

Electric and magnetic systems have been roposed to obviate theblackening of the bulb, but they are relatively complicated anddifficult to utilizein practice. Another method consists of placing apowder in the bulb ing the bulb. This method, of course, requires aspecial manipulation "of the bulb by the user.

According to my invention, blackening of the bulb is prevented by theinterposition, in

the path of the convection currents, of av shown in 0 with which thewalls are cleaned by revolv In the drawing, Fig. 1 is an elevation of anincandescent electric lamp showing the convection currents therein;Figs. 2, 3 and 4 showvariations in the arrangement of the screens withinthe bulb; and Figs. 5 and 6 show different forms of screens.

Referring to Fig. 1, the lamp comprises a 'bulb 10'and base 11. Afilament 12 is connected to inner lead wires 13 sealed into'a stem press14. An arbor 15 is sealed to the stem press 14. The arrows show thedirection of the convection currents inside of the bulb. These currentsrise vertically from the filament to the neck of the bulb, then followthe walls of the bulb down to the bottom thereof. Referring to Fig. 2,the screen 16 comprises a conically wound spiral of wire consisting of ametal such as tungsten, molybdenum, nickel or iron, which is sup ortedby wires 17 sealed into an arbor 18. 11 their u ward travel, theparticles breaking oil the filament, come in contact with the screen 16to which they adhere, thereby preventing their deposit upon the walls ofthe bulb. Referring to Fig.v 3, a spiral of wire 19, forming the screen,is simpliy wound upon an arbor 20 of a lamp.

Re errin to Fig. 4, a screen 21, of the form igs. 5 or 6, is shownsupported on wires 22 sealed into an arbor 23. A piece of mica 24deflects the upward rising current of gas so as to protect the base ofthe bulb from the intense heat.

As shown in 'Fig. 5, the screens may take the form of a wire clothconsisting of a metal such as tungsten, molybdenum, nickel or iron.Another form, shown in Fig. 6, comprises a perforated foil which mayconsist of a metal, such as hereinbefore mentioned, or of a nonmetallicsubstance such as glass or mica.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a gas-filled electric lamp, the combination of a light sourcecomprising a refractory metal adapted to be heated and a screen membercomprising a hollow body having a 90 multiplicity of openin in the sidesthereof located above said lig t source when said lamp is in use andextending longitudinally of said lamp.

2. In a gas-filled electric lamp, the combination of a light sourcecomprising a filament distributed about the longitudinal axis of saidlam and a screen member comprising a ollow body having a multiplicity ofopenings in the sides thereof located above said light source when saidlamp is in use and extending longitudinall of said lamp and having itsaxis substantlally coinciding with the said longitudinal axis of thesaid lamp.

In witness whereof, I have hereunto set my hand.

- JEAN QUESSEQUE,

